Update .gitlab-ci.yml

.gitlab-ci.yml

 image: python:3.7.1-slim
-
 pages:
+ 
+pages:
+    stage: deploy
     script:
+        - mkdir .public
+        - cp -r * .public
+        - mv .public public
         - pip install mkdocs
         - pip install mkdocs-material
         - mkdocs --version
         - mkdocs build
+    artifacts:
+    paths:
+        - public
+    only:
+        - pages
+    tags:
+        - general
     artifacts:
         paths:
             - public